Air ducts, such as that used with central furnaces and air conditioning units and the like, are typically made from sheet metal or a plastic flexible material having cylindrical, rectangular, or other cross sections as are well known in the art. The ducts are conventionally joined by sliding an end of one duct into an end of another duct and fastening and sealing the joint with duct tape, fasteners and/or other sealants. Often ducts are joined to one another or to an air conditioner/heater unit or a vent using a fitting in a similar manner.
Unfortunately, over time the seal fails and air is permitted to escape from the duct joint. In many cases the mechanical connection is partially or fully broken. Thus, air from the duct system leaks into areas of the building where the air is neither intended nor desired, such as in the attic, basement, or between the walls. Consequently, the energy that was used to heat or cool the escaped air, in addition to the energy used to move the escaped air, is wasted.
Attempts to prevent the unintentional leakage of air from duct joints include placing a gasket between the two ducts. While gaskets prevent air from leaking out of the duct joints, the ducts still require some fastening mechanism to prevent the ducts from slipping apart during installation as well as over time. Thus, it is good practice to securely fasten the joints of a duct together, and in fact the Uniform Mechanical Code .sctn.602.4 requires a mechanical connection between joints. Sheet metal screws or other similar fasteners are sometimes used to prevent partial or complete disconnection of the ducts and to meet the requirements of the Uniform Mechanical Code. However, the installation of the duct system requires holding ducts in place while fastening the joints, which can be awkward and time consuming and is often simply not done, particularly when the installer is uninformed or is in a hurry. Consequently, many duct joints are held together with nothing more than duct tape, which quickly fails permitting partial or complete disconnection of the ducts.
Thus, there is a need for a duct joining system that quickly and easily fastens and seals ducts together to form an air-tight conduit.